ISOLATION OF LIPOLYTIC SUBSTANCES CAFFEINE AND 1,7-DIMETHYLXANTHINE FROM THE STEM AND RHIZOME OF SINOMENIUM-ACTUM

We attempted to isolate lipolytic substances from the stem and rhizome of Sinomenium actum Rehder et Wilson by using high-performance liquid chromatography (HPLC). S-I and S-II were isolated from the fractions showing lipolytic activity. S-I and S-II were identified as caffeine a nd 1,7-dimethylxanthine, respectively, by direct comparison with authe ntic samples. Caffeine (S-I) dose-dependently stimulated lipolytic act ivity in isolated fat cells of rats, at concentrations of 500 to 1000 mu M. 1,7-Dimethylxanthine (S-II) also stimulated lipolytic activity a t concentrations of 500 to 1000 mu M. Furthermore, we found that caffe ine and 1,7-dimethylxanthine enhanced catecholamine-induced lipolysis at lower concentrations of 0.1 to 1 mu M.